Custody versus Guardianship of minor children. I have seen a number of instances where a parent gives his or her children to their own parent. A child whose parent gives the child to the grandparent to take care of.
Without some legal process, the grandparent cannot really do much. Sure, the grandparent can provide room and board, but not much else. The grandparent lacks the legal ability to consent to medical treatment, handle school enrollment, and many other issues. What can be done?
The options range from a guardianship, through a custody case, to adoption. The guardianship is the least invasive for the parent, and the easiest for the parent to set aside. Adoption is the other extreme, in that the parent will no longer be the parent, and will have no rights to the child. Custody is between, and provides the grandparent with full legal abilities and rights, but is much more difficult to reverse -- it also sets out the parent's limited rights to visit with the child, and under what conditions, as well as can require the parent to financially assist the grandparent with the costs of raising the child.
A guardianship is appropriate when there is a disability. The example I like to use is that the parent is involved in a car accident and is hospitalized and in a coma. Obviously the parent cannot care for the child. If the doctors think that parent may be in a coma (for medical reasons or otherwise) for some time, then grandparent can be appointed the child's guardian to take care of the child, including having legal rights like a parent.
Once the parent is cured, and up and about, the disability has ended, and the guardianship will end. Understand that the standard concerns the parent's ability, not the child's best interests.
Custody orders can issue under the same type of disability, but would not terminate so automatically. The real issue would be the best interests of the child, not "is the parent better". Depending on the disability, this point can be very important, such as the parent being involved in a drug lifestyle. Sure, the parent may claim drug use has ceased, but has the parent really changed? Has the parent obtained a job, good housing, and the appropriate social support network to handle raising a child, or is the parent merely putting on airs?
It would be the parent's burden to prove that there has been a material change in circumstances such that it would be in the child's best interests to return the child to parent. The focus being on the child.
In an adoption, the parent's rights are terminated. Absent very unusual circumstances (something like fraud), an adoption cannot be reversed.
So, any person in "grandparent's" position should really think about which option best serves the child's interests.